A total of 23 athletes at the first Youth Olympics in Singapore in 2010 went on win Olympic medals in 2012. Perhaps the most memorable was South African swimmer Chad le Clos, who beat Michael Phelps in the 200m butterfly.

Le Clos, now 22, was far more successful at the Youth Olympics, where he won five medals, including silver in the 200m fly.

“It taught me a lot of lessons that I wouldn’t have learned,” le Clos said. “A lot of people told me when I was younger that I wasn’t going to be a great butterfly swimmer. I shouldn’t even try to compete. Look at me a couple years later.”

Le Clos is in Nanjing, China, as an athlete ambassador this time around.

“To think that I’m an inspiration to young kids out there is a blessing,” he said. “I know what it feels like. I was one of those kids who looked up to many people.”

Le Clos relives his victory over Phelps in the above clip, but he did not go up against Phelps at the Pan Pacific Championships last week. South Africa did not send its best swimmers to the event after they took part in the Commonwealth Games. Le Clos won seven medals at Commonwealths.

“I needed some time out from competing after the Commonwealths, not have the stress of competing all the time,” Le Clos said, according to SwimSwam.